I am trying to find the following 2 limits as part of a series of 4 exercises following out lectures. We haven't really learned derivatives yet, so I can't just slap L'Hospital and be done with it.
The first two I could solve with Taylor Expansions, but I still need to solve:
limx→0ex−sinx−1x2
Taylor Expansion of sin didn't work here, and I don't know how to deal with the ex.
limx→0xsinxcosx−1
Given −sin2x=cos2x−1 I tried multiplying by cosx+1cosx+1, which lead me to −xcosx −xsinx and then I don't know what else to do. (SOLVED) I suppose I could simplify this to −xcotx−xsinx, which leads to -2.
Answer
You have
ex=1+x+x22(1+ϵ1(x))
and
sin(x)=x+x2ϵ2(x)
cause x↦sin(x) is odd.
then the limit is 12
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